Cargo container operators, shipping logistic entities, or freight operators often need to manage and track a large fleet of cargo shipping containers or trailers (as used herein, the term “container” will be used generally to include cargo and other types of containers, storage areas, and/or trailers). However, it can be difficult to tell which containers are full and which are empty or to track full and/or empty containers, for example, in a shipping yard filled with cargo containers.